Thursday, November 13, 2008

TE 303 - HW #7, P3 - ΔSSys, ΔSRes, and ΔSUniv, for a H.T. Process - 15 pts

During the isothermal heat addition process of a Carnot Cycle, 900 kJ of heat is added to the working fluid from a source at 400oC. Determine:

a.) the entropy change of the working fluid
b.) the entropy change of the heat source
c.) the total entropy change of the universe for this process.

1 old comment

3 comments:

Dr.P said...

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HINTS:
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* If the system is isothermal and reversible, then change in entropy can be evaluated from the definition of entropy.

* Be careful with the sign for each Q.

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ANSWERS:
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deltaS = 1.34 kJ/K (fluid)

Anonymous said...

How is the change in entropy found for the heat source? I can not find an equation in the book for dSresv.

Dr.P said...

Dear Anonymous,

Whether you are looking at the surroundings (reservoir) or the system (fluid), the equation is the same: entropy change = entropy transfer plus entropy generation, or deltaS = integral(dQ/T) + Sgen.